Circuit breakers



K 7 0/2 iwi Y 1NVENTOR5 ATTORN March 25, 1958 P. M. CHRISTENSEN HALCIRCUIT BREAKERS Filed NOV. 2, 1955 United States Patent i CIRCUITBREAKERS Paul M. Christensen, West Orange, and Dominik Wiktor andJohnBryan, Newark,--N. J assig'nors to Federal Pacific Electric Company,acorporation ofDelaware Application November 2', 1955,Serial No. 544,465

19 Claims. (Cl'.-200--1-16) The. present; invention relates tocircuitbreakersand in particular to small molded-case breakers of thetype employedv in lighting: distribution panelboards and in domesticcircuit protection in lieu of fuses. I

An. objectofthe invention is to provide-a small circuit breaker of novelconstruction having quick-break characteristics whenmanually operatedfor opening'the contacts, even if the" person operating the handleshould arrest. the handle part way toward open position. A furtherobject of the invention is. the provision of such a novel circuit.breaker having quick-break characteristics without resort toanover-center spring.

Small-circuit'breakers have been widely used in which a'moving contactis operated from open circuit toclosed circuit condition; and reversely,in which an over-center spring: is employedior biasingthe movingcontactboth in the closed'and in the open direction, depending: on theconfiguration of the operating mechanism. Overcenter springs havetheimportant disadvantage of. exerting zero force: at the moment that theypass dead center; At such time, there: is the Zerocontact: pressuref andthere is also zero: tendency of thespring to drive :the contacts apart,while this condition theoreticallyiexists at' only aninfinitesimal pointin the. opening stroke of the operating handle, as a practical matterfriction enters the picture so that an appreciable portion of'the'operating stroke maybe found to give weak and uncertain contactpressure. If the handle" were deliberately operated in a decisive strokethen there would be no'proble'm. How'- ever, there is the possibilitythat one might deliberately retard the handle, or operate itverygradually; and the specifications of some users concerning circuitbreakers require quick closing and quick opening despiteall po'ssibl'edeliberate attempts to control the operation of the handle.

The present invention is concerned with a type of circuitbreaker inwhich a spring is arranged to bias the contactsv away from each other atall times, even when the contacts are'closed, in contrast to over-centerspring mechanisms; When the breaker is closed, a locking mechanism holdsthe contacts closed", against this spring bias. When" the lockingmechanism has been released manually, the spring is fully effective atthe very start of the opening stroke't'o drive the contacts apart. Sucha circuit breaker is improved, according to the present invention, toavoid all possibility of hindering the opening by mis-operation of thehandle.

A further'object ofthe invention is to provide a novel small circuitbreaker. with quick-make andquick-break characteristics when operatedmanually without: resort to over-center springm'echanisms for operatingthe movable contact. It is understood thatthe circuit breaker shouldalso have quick-break characteristics when automatically tripped by anoverload. v

The foregoingobjects are. achieved in thenovel illustrative circuitbreaker. described below in detail, in which certain additional featuresof novelty and advantages 2,828,388 Patented Mar. 25, 1958 ice willibeapparent. Inthe detailed description, reference is made to theaccompanying drawings, wherein:

Fig. 1 is a lateral view of a circuit breaker embodying the inventionwithportionsof the enclosure being broken away to reveal the internalmechanism;

Fig. 2 is a similaryiew with the handle in a shifted positioncompared toFig Land with certain parts shown in dotted lines torepresentastillfurther operating position.

Fig. 3 is airagrnentary cross-section of a portion of the novel circuitbreaker along-the line 33 in Fig. 1-.

Fig 4 is a fragmentary cross-section of the novel circuitbrea'keralongtheline l -40f Fig. 3.

Fig.7 5 is arr-enlarged fragmentary cross-section of a portion of: thenovel apparatus along the line 5-5 in Fig.1.

Fig 6 is aperspectiveof the handle of the circuit breaker in. Figs. 1,2- andS and Fig. 7 is a perspective of the element in Fig. 1- thatcooperates with the'h'andleshown in Fig. 6.

Referringnow to the drawings; there is shown a pair of housing;v members10'and 12 of molded insulation which supporb'and enclose the operatingmechanismof the novelcircuit breaker. This includes a fixed contact 141-on an external terminal'member 16; movable contact 1 8onr contactcarrier 20,. having a coil-spring pivot 22, contact 18 being shown tothe left' of pivot 22; an .actuator' 2'4h'aving: a. pivot-26 in contactcarrier 20 to the right of; coil-spring. pivot 22; a' current-responsivebimetal=2'8united :at its'lett end to contact carrier 20 and at itsright end-being in latching. engagement. with actuator 24;:and a secondterminal 30'con'nected by flexible braid 321 to the curre'nt responsive'bimetal 28 near the latchend of this bim'eta'li A. bimetal 24a forcompensating for ambient temperature variations is as shownwhich may beregardedas a part of actuator 24. The current path through thecircuit-breaker thus far described ex tends from terminal 1 6, throughfixed and'm'ovable contacts 1'4 and 18',- through contact carrier 20,.b'im'etal- 28 and flexible braid 32 to terminal 30- which is designed tostab int'oa live" bus receptacle; Bivot" 26 embodies insulation (notshown') to interrupt anyposs'ible current path from bimetal 28 throughactuator 24"t'o contact carrier 20. e

The contact carrier is shown in it's closed position with movablecontactl 8 b'ea'ring against fixed conta'c't 1 4. The mechanism for operatingcontact car-rier20' between its closed and open positions is a'sfollowszA link 34 which is a U-shaped piece of stiffwir'e ha's the sides of theU disposed perpendicular to the view so as to form two'pivotsi Oneofthes'e has a bearing in the upper end of the actuator 24 and the otherhas a bearing in a member 36(Figs. 1, 2, 5 and 7). Handle 38, pivoted onan integral stub shaft 10a (Fig; 5'), operate's member 36"to close thecircuit breaker when shifted to the extreme left in Fig. l, and thishandle opens the circuit breaker when it is shifted to the right. The cooperation of members 36 and 38 will be discussed in detail below. In theconfiguration shown, member 36 and element 34' constitute a pair oftoggle members which are slightly over center. The extent ofover-centering is limited by engagement of'member 36 against an int'egral stopj 4(lformed in insulating housing member 121 A similar stopportion is formed in housing portion 10 which is broken away from theview in Fig; 1. The pivotal connection between members 34 and 36(Fig. 1) is above the center line extending from the pivotal axis ofmember 36 to the pivot axis of member 34 in the actuator 24; In thiscondition the toggle is said to be locked. V

Pivot spring 22 which appears in Figs. 1 and 2' and is I! 6 shownsomewhat enlarged in her of purposes. In the form of circuit breakerillustrated, all of the elements between the toggle member 36 and thefixed contact 14, including elements 34, 24 andZfi, are rigidin thisillustrative circuit breaker. When toggle 34, 36 is in the positionshown, a degree of resilience is introduced in the mechanism whichenables contact 18 to bear against contact 14, despite reasonablevariations in the parts dimensions in volume manufacture of such circuitbreakers. In this function, spring 22 serves as a pivot and it alsofunctions with upward spring bias to swing contact carrier 20counterclockwise about pivot 26 to develop contact pressure when thetoggle 36, 34 is locked and pivot 26 is fixed. A compression spring 44is shown that acts between the contact carrier 20 and member 36, in thedirection to open the contacts and to shift member 36 and handle 38 tothe off or reset position. The force of spring pivot 22 to bias thecontacts closed when the toggle is locked is considerably greater thanthe reverse action of spring 44. Nonetheless spring 44 biases thecontact arm 20 in the opening direction to be instantly effective toopen the contacts when the toggle is released.

The linkage including toggle 34, 36 and actuator 24 is effective tooperate the contact carrier 20 into closed configuration only when thelower tip of actuator 24 is arrested by the end of bimetal 28. Thisbimetal may be described as a current-responsive latch which arrestsactuator 24. The handle 38 and toggle 34, 36 operates through actuator24 to operate carrier 20 for closing the circuit breaker when theactuator is latched. When current passes through bimetal 28 it heats andcurves downward. It passes out of latching engagement with actuator 24when a critical temperature is exceeded corresponding to the currentrating of the circuit breaker.

A rigid soft iron bar 42 is united to contact carrier 20 at the samepoint where bimetal 28 is anchored. In the event of a very suddenoverload current through bimetal 28, the resulting flux developed bythat current about the bimetal links bar 42. A downward deflecting forceis developed, flexing bimetal 28 toward bar 42 and out of latchingengagement with actuator 24.

When current-responsive latch 28 releases actuator 24, either because ofthermal effect or magnetic effect, actuator 24 swings clockwise aboutits pivot 26. Compression spring 44 then operates to drive contactcarrier 24) counterclockwise. Toggle 24, 26 is not effective to preventsuch motion, when actuator 24 is released. Compression spring 44separates the contacts at high velocity when current-responsive latch 28releases actuator 24. There is no lack of spring pressure to open thecontacts following the instant that actuator 24 is released, nodead-center condition such as is involved in over-center springmechanisms.

Apart from the snap action found in opening the contacts after releasedue to overload, the present circuit breaker operates with snap actionboth in opening and in closing the contacts in response to manualoperation of handle 38.

Handle 38 is operated from the extreme right position (not shown) to theextreme left position shown in order to close the circuit breaker. Whenthe handle is operated in this fashion toggle member 36 is operatedcounterclockwise and toggle member 34 applies thrust to actuator 24 inorder to actuate contact carrier 20 in the clockwise closing direction.A V shaped member 46 is rockably mounted on contact carrier 20 and,during contact-closing travel of the contact carrier, member 46 isbiased by spring 44 so that the left-hand arm of member 46 travels alona cam surface 48 formed in the insulating housing parts and 12. Theupper end of the cam surface 48 has a shoulder which arrests member 46as well as contact carrier 2:?- at a point prior to engagement ofcontact 18 against contact 14. Thereafter further operation of handle 38in the closing direction drives toggle member 34'and actuator 24 withoutcorresponding travel of con- Figs. 3 and 4, serves a numtact 18. Duringthis further travel, spring pivot 22 becomes stressed so as to assumeapproximately the position in Fig. 3. This stress shifts contact carrier20 downward and somewhat to the right in Fig. 1, and operation of member36 counterclockwise also shifts spring 44 against the righthand arm ofmember 46. The result of both these actions is to shift member 46 out ofengagement with the shoulder portion of cam 48. Thereafter pivot spring22 drives contact 18 against contact 14 with a snap action. At thisphase of the operation toggle 34, 36 has been shifted over-center and isnearly against stop 46. Compression spring 44 is ineffectual to separatethe contacts at this stage. Snap-closing of the contacts cannot beavoided even by deliberate, slow operation of the handle 38 in theclosing direction. 7

As seen in Figs. 5 and 6, handle 38 is supported on a bearing 19a formedas a projection extending from housing wall 10. Ann. 38a extends out ofthe casing 10, 12 as an integral operating lever. Annular bearingportion 38b is of limited axial thickness, the space between members 12and 10 being filled by a flange extension 380 of the handle 38. Thearcuate extent of flange 38c about bearing 10a is here shown as about 10less than that between shoulders 36b and 360 of toggle member 36 (Fig.

'7). This difference in arcuate extent of the flange 33c and the spacebetween the shoulders of toggle member 36 enables handle 38 to pivotwith limited lost motion without affecting toggle member 36. Handle 38is held against shifting from the position in Fig. 1 to that in Fig. 2by a leaf-spring detent 50 received in an appropriate recess in member12, a similar recess also being formed in housing member 10. Flange 38cand portion 38b close off the opening in housing 10, 12 required for theoperating stroke of handle 38a, preventing access to the mechanism andminimizing the number of crevices into which operation- -hindering dirtmight collect. Handle 38 is operated clockwise in the opening directionwithout affecting member 36, until handle 38 reaches the positionrepresented by the solid lines in Fig. 2. In this phase, flange 38cleaves shoulder 36!) and reaches shoulder 360, a lost-motion operation.Further shifting of handle 38 counterclockwise into the dotted lineposition causes toggle 34, 36 to shift overcenter into the dotted lineconfiguration shown in Fig. 2. Manual retention of handle 38 in thedotted line position can no longer restrain contact carrier 20, forthereafter spring 44 drives the contact carrier into open position, withportion 52 of contact carrier 20 against stop 54 formed on the inside ofhousing walls 10 and 12. With the handle restrained, toggle member 36moves clockwise and reversely takes up the space between flange 36c andshoulder 3612. If handle 38 is released in any stage short of full offposition, spring 44 completes the reset of the handle, thereby forcingthe handle into reset position in condition to close the breaker whendesired. During the manual opening stroke actuator 24 remains oppositethe end of bimetal 28.

Spring 44 is effective to return actuator 24 from the clockwise positionassumed after release of the circuit breaker by current overload andinto normal position ready for reclosing, by virtue of a roundedright-hand lower end of bimetal 24a, suitably polished, that slides overthe top surface of bimetal 28 during such reset operation of thebimetal.

In the event that handle 38 should be mechanically locked in on positionfollowing automatic tripping in response to an overload, member 24remains in its tripped position (clockwise relative to that illustrated)while the bimetal cools. When the handle is thereafter operated to offposition, it takes up the lost motion and then can drive the linkage 36,34, 24 into reset configuration, with the tip of the bimetal 24aopposite the end of latch member 23. Spring 44 naturally tends to effectthis reset; but incase friction of actuator 24 in moving across the topsurface of member 28 should prove too great for this action, positiveoperationof the handle will effect breaker.

Also, in' case this invention is appliedts a circult" breaker in 'at'its left end, this specalized condition of frictionally-inhibited resetafter automatic trip does not occurf The"fo'regoing disclosurerepresents the presently preferred embodiment of the invention,as'applied'to a known form of circuit breaker, but'it should not beinferred the invention is limited to this-specific form of circuitOtherforms omitting'bir'netal- 24zz m'ay be desired; resilience maybeintroduced using "a rigid pivot in place of spring pivot 22; andsnap-closing is not dependcut on the particular form of'mech ani's'mshown. Therefore it'is appropriate that the inventionshould beconstru'ed broadly in accordance withits full spirit and-scope.

What is claimed is:

1. A circuit breaker including an insulating enclosure, a'fixed contactmounted therein,a movable contact carrier bearing a movable contact, acurrent-responsive latch carried by said contact carrier, an actuatorpivoted to said contact carrier and engageable with saidcurrent-respon'sive latch, said actuator when engaged with said latchbeing operable thereafter to actuate said contact carrier for closingthe contacts, a toggle including a first toggle member pivoted to saidactuator and a second togg'lemember pivoted to said'insulating housingand-pivotally connected'tosaid first toggle member, a compression springhaving one end acting against said contact carrier and having itsopposite end acting against-said second-toggle member and beingcontinuously effective to bias said contact carrier and said secondtoggle member toward their respective circuit-breaker-openpositions,

and saidtoggle being effective to operate saida'ctuator and thereby tooperate said contact carrier to circuitbreaker-closed position againstthe bias of said spring,

said toggle shifting over center into locking position when thecircuitbreaker is closed, a handle for said second toggle member havinga portion thereof projecting out'of the enclosure through an aperturetherein and being operable to shift said second toggle member overcenterin one direction to close the circuit breaker and said handle beingreversely operable to release the toggle, there being a lost motionconnection between said handle and said second toggle member wherebythe-toggle, when shifted from circuit-breaker-closed configuration andover-center moves out of the locking position and enables thecompression spring to drive a contact drivethernovable" contact from"open" to closedposition, said mechanismincluding yielding spring-"means and a detent' i arresting the closin'g"motion* of' -the movablecon tact me'rnberduringclosin'g operation of the h'andleysaid yieldingspring means producing'snap closing of the contacts'aft'er releas'e of'thedetem; means lockin'g the con- --tac'tsclosed-, spring-means-at alltiines biasing the contacts =toward open position; and a-lost-motionconnection between said handle and said contac't-carrier effective torelease the" locking means and thereby"enable said biasing spring toopen -the contacts despite-possible' arresting of the handle part waytoward open position after carrier into circuit-breaker-open positiondespite possible arresting of said handle during its circuit breakeropening stroke, said spring being effective when the handle is releasedduring an opening stroke to operate said toggle and said handle intoextreme open position, in condition for a reclosing operation of thecircuit breaker.

2. A'circuit breaker in accordance with claim 1 wherein said handleembodies an arcuate flange concealing said second toggle member in alloperative positions of the portion of the handle projecting through saidaperture.

'3. A'circuit breaker in accordance with claim 1 wherein said handle andsaid second toggle member have coaxial pivots, said handle embodying anarcuate flange closing off the aperture in the housing in all positionsof the handle, said flange having a concave bearing surface and saidsecond toggle member having a complementary arcuate convex bearingsurface with shoulders at the arcuate extremities thereof, the arcuateextremities of said flange coacting with said shoulders for operatingthe toggle, the arcuate extent of said flange being appreciably lessthan the arcuate separation between said shoulders and therebyestablishing said lost motion connection between said handle and saidsecond toggle member.

4. A circuit breaker including an insulating housing having an aperturetherein and containing the operative mechanism thereof, said mechanismincluding a fixed contact, a movable contact carrier bearing a movablecontact, a handle projecting from said aperture and operativelyconnected to said movable contact carrier to release of said'lockin'gmeans.

SEA-circuit breaker including an insulating housing having an aperturethereinand containingthe operative mechanism thereof, said nie'chaiiism'including a fixed contact, a movablecontact carrier bearing a'movablecontact, a handle rotecting-from said aperture and operativelyconnected-to said movablecontact carrier to drive the; movable contactfrom open to closed position, rrieans for locking the contacts closed,spring means at' all times biasing'tlre contacts toward open position,

said spring means alsobei'ng a'r'ranged to drive thehandle-in'thecontact-openingdirection upon release of the 'lockingmeans,and a lost motion connection between said handle'an'd-said locking meansproviding for limited idle operation of-sa'id ha'ndle in'relation to thelocking means'followed by'relea'se' of the locking means by thehandleup'on further operation thereof inthe releasing direction, andsaid spring being efiective thereafter to "snap-open the'c'ontactsfreeof inhibitingaction by said handle:

6. A circuit breaker having an insulated housing formed with an apertureand containing the operative circuit breaker mechanism; a pivotedhandlehaving a flange closing said aperture and having a manually engageableportion'projecting externally of=the housingthrough said aperture, amember=pivoted in thehousing coaxially with said handle andhavingarcuately separated shoulders disposedfor coaction with the arcuateex'tremities of the handle flange, said extremities being separated by asmaller angle than the separation between said shoulders whereby toestablish a limited lost-motion connection between said 'handle and saidmember, afixed contact in said housing,

a movable contact cooperable therewith and movable between open positionspaced from said fixed contactand closed position against said contact,a'spring operative at all times to bias said movable contact toward openposidemand to bias said shouldered member toward circuitbreaker-openposition, a linkage operated by said member to drive said movablecontact toward'circuit-breakerclosed position against said spring biasand including means locking the circuit'breaker closed, said handlebeing effective to shift said shouldered member to release the lockingmeans and said biasing spring being thereafter effective to open thecontacts, said handle being ineffective to' arrest the opening of thecontactsafter release of the locking means by virtue'of the lostmotionbetweensaid handle and said cooperating member, said biasingspring being, effective upon release of the handle to shift the handleinto circuit-breaker-open position.

7. A circuit breaker having an insulating enclosure formed with anaperture, a pivoted handle extending from said aperture and having anarcuate portion closing the said aperture in all operative positions ofthe handle'and having an operating portion projecting externally of thehousing through said aperture, a pivoted member'cooperating with saidhandle and formed with spaced shoulders, said handle also having spacedportions coacting with said shoulders, the spacing between said handleportions and the spacing between said shoulders being different andforming a lost motion connection, a fixed contact'in said enclosure anda contact carrier bearing a movable contact coacting with said fixedcontact, a biasing spring arranged to provide contact opening bias inall said handle and including means for locking said contacts whenclosed by handle operation, said linkage including a current-responsivelatch and an actuator cooperating with said latch, said latch beingarranged upon current overload through the circuit breaker to releasesaid linkage and enable said biasing spring to open the contacts, saidhandle also being effective to release said locking means, thereby toenable said biasing spring to open said contacts, said lost motionconnection preventing said handle from interfering even if held inlocking-means-releasing position.

8. A circuit breaker including an insulating enclosure having anaperture therein, separable contacts in said enclosure, a handleextending from the interior of the enclosure through said aperture, saidhandle being operable in reverse directions to open and to close thecircuit breaker, a linkage connecting said handle to operate one of saidcontacts, said linkage including a mem her in the enclosure cooperatingwith said handle through a lost motion connection therewith, a springbiasing the contact carrier toward open circuit position in allconfigurations of said linkage and said linkage having locking meansholding the contact carrier in closed position despite said biasingspring, said locking means being releasable by said handle, said linkagefurther including a current-responsive latch and an actuator cooperativewith said latch efiective to release said linkage for circuit breakeropening operation in response to overload current, said spring alsobeing effective to opentsaid contacts when said handle is operatedtoward circuit breaker opening position and after release of saidlocking means despite possible interruption of handle operation inlocking means releasing position.

9. A circuit breaker in accordance with claim 8 wherein said operativelinkage includes yielding springimeans interposed between saidcooperating member and said movable contact carrier, detent meansarresting said contact carrier during closing operation of said handle,said arresting means being arranged to release the contact carrier forsnap closing of the contacts under the influence of said yieldablespring means during further contact closing operation of said handle,thereby to cause snap-closing of the contacts as well as snap-opening ofthe contacts irrespective of gradual operation of the handle in bothdirections.

10. A circuit breaker including a fixed contact, a movable contactcarrier bearing a movable contact and having a supporting pivot, anactuator carried by said contact carrier, a current-responsive latchcarried by said contact carrier, said contact carrier and said actuatorand said current-responsive latch being held in substantially rigidtriangular assembly when said contacts are closed and said actuatorbeing releasable by said latch upon overload, a first toggle memberpivoted to said actuator, a

second toggle member having a fixed pivot and further having a pivotalconnection to said first toggle member, and a spring continuously actingin compression between said second toggle member and said contactcarrier in contact-opening direction and in the direction to drive saidsecond toggle member toward normal open-circuitbreaker position, ahandle cooperablewith said second toggle member and having a lost-motionconnection thereto for operating said toggle members in one directionover center into contact-closed position and operable in the reversedirection to shift the toggle from contactclosed position and overcenter, with the lost-motion connection thereafter being'efiective toinsure operation of the contact carrier into open position despite thepossibility of said handle being arrested. 7

11. A circuit breaker including a first contact, a movable contactcarrier bearing a second contact, engageable with the first contact, acurrent-responsive latch operable .to maintain said contacts closed andto release the. contact carrier-for opening said contacts inrespouse toa current overload, and actuating mechanism for said movable contactcarrier including a first toggle member operatively connected to saidmovable contact carrier, a second toggle member having a first pivot andhaving a pivotal connection to said first toggle member spaced from saidfirst pivot, said toggle members being movable over center in reversedirections to close and open said contacts, a spring continuouslybiasing said contact carrier in the circuit-opening direction andcontinuously biasing said second toggle member towardopen-circuit-breaker position, an operating member having a lost-motionconnection to said second toggle member and effective to operate thetoggle from open contact position over center to closed contactposition, said operating member being operable reversely to operate thetoggle from closed contact position and over center, said biasing springbeing then operative to open the contacts, the lost-motion connectionbeing effective to prevent the contacts from being retarded by arrestingthe manual operator, said actuating mechanism for the moving contactcarrier including a detent for arresting the movable contact carrierwith the contacts separated during closing operation of said operatingmember and a yieldable spring enabling continued operation of the manualoperator in the closing direction after the contact carrier is arrestedby the detent, whereby release of'the detent will allow said yieldablespring to close the contacts abruptly, to achieve both snap-opening andsnap-closing of the contacts by operation of the manual operator,despite gradual operation thereof.

12. A circuit breaker including a fixed contact, a movable contactcarrier bearing a movable contact, an operating mechanism including amanual operator effective to move said movable contact carrier fromcircuitbreaker-open position to circuit-breaker-closed position andincluding a snap-closing spring, support means for said mechanism, andmeans cooperating with said support means and effective during a closingstroke of said manual operator to arrest the advance of the movablecontact carrier and' thereafter being efiective to release the movablecontact carrier for abrupt closing of the contacts by said snap-closingspring, a contact-opening spring operatively connected to said contactcarrier so as to bias the contact carrier in the contact-openingdirection in all phases of circuit-breaker operation, said operatingmechanism including means locking the contact carrier in closedposition, and a current-responsive overload release for said lockingmeans, said manual operator having a lost-motion connection to saidmechanism and being efiective to release said locking means for openingof the circuit breaker by said opening spring, said lost motionconnection preventing the manual operator from retarding opening of thecircuit breaker after said locking means has been released.

13. A circuit breaker including art insulating housing having anaperture therein and containing the operating mechanism thereof, saidmechanism including a fixed contact, a movable contact carrier bearing amovable contact, a handle projecting from said aperture and operativelyconnected to said movable contact carrier to drive the movable contactfrom open to closed position, said mechanism including yi lding springmeans and a detent arresting the closing motion of the movable contactmemher during closing operation of the handle, said yielding springmeans producing snap-closing of the contacts after release of thedetent, current responsive means and locking means controlled therebyfor holding the contacts closed, and a lost-motion connection betweensaid handle and said locking means providing for limited idle operationof said handle in. relation to said locking means followed by release ofthe locking means by the handle when the handle is moved in thereleasing direction, and said lost-motion connection accommodatingreverse relative idle operation of the locking means when the springdrives the contacts open free of all possibility of retarding control bythe handle.

14. A circuit breaker including an insulating housing having an aperturetherein and containing the operating mechanism thereof, said mechanismincluding a fixed contact, a movable contact carrier bearing a movablecontact, a handle projecting from said aperture and operativelyconnected to said movable contact carrier to drive the movable contactfrom open to closed position, current responsive means, locking meanscontrolled by said current responsive means for holding the contactsclosed, said mechanism including a lost-motion connection having a firstpart on the handle driving side and having a second part on the drivenside of the connection and a spring acting against said second part ofsaid lost-motion connection and effective to bias said handle in theopen direction when the circuit breaker is open, said spring also actingat all times on said movable contact carrier for biasing the contacts inthe opening direction.

15. A circuit breaker having an insulating enclosure formed with anaperture, a pivoted handle extending from said aperture and having anarcuate flange closing said aperture in all operative positions of thehandle and said handle having an operating portion projecting externallyof the housing through said aperture, an operated member pivotedcoaxially with said handle and having a convex curved surface matingwith a concave curved surface of said arcuate flange, said operatedmember having shoulders cooperable with the arcuate extremities of saidflange and said shoulders being spaced further apart than said shoulderswhereby to afford limited arcuate operation of the handle withoutenforcing corresponding operation of the operated member, and circuitbreaker mechanism contained within said enclosure and including a pairof contacts operable by said operated member for closing and opening ofthe circuit through the circuit breaker.

16. A circuit breaker in accordance with claim wherein said enclosureincludes confronting walls one of which provides a bearing for saidhandle and the other of which provides a bearing for said operatedmember, said operated member providing a further bearing support for thehandle by virtue of the convex arcuate surface of the operated memberand the cooperating concave arcuate surface of said flange.

17. A circuit breaker including an insulating housing having an aperturetherein and containing the operative mechanism thereof, said mechanismincluding a first contact, a movable contact carrier bearing a secondcontact cooperable with said first contact when the circuit breaker isclosed, a current responsive device carried by said movable contactcarrier, a member pivoted to said contact carrier and movable intolatching engagement with said current responsive device, a pivotedhandle for operating said mechanism projecting exteriorly of saidhousing, a toggle for operating said member into latching engagementwith said current responsive device and efiective thereafter for drivingsaid contact carrier to close the contacts, said toggle including afirst member pivoted coaxially with said handle and a second memberinterconnecting said first toggle member and said latching member, saidhandle having a lost-motion connection to said first toggle member, anda spring acting between said contact carrier and said first togglemember and effective to bias the handle in the opening direction and thecontact carrier in the opening direction when the circuit breaker isopen and effective to maintain contact opening bias on the contactcarrier when the circuit breaker is closed, said lost-motion connectionenabling limited idle movement of the handle in the contact openingdirection followed by operation of the toggle in the contact releasingdirection to enable the spring to open the contacts, and to enable thespring to provide drive for said handle via said first toggle member inthe open" direction of handle operation.

18. A circuit breaker including an insulating housing having an aperturetherein and containing operative mechanism thereof, said mechanismincluding a fixed contact, a movable contact carrier bearing a movablecontact, an actuator and overload release means cooperable with eachother and carried by said movable contact carrier, a handle projectingfrom said aperture and operatively connected to said movable contactcarrier via said actuator when the latter is in cooperative relationwith the overload release means to drive the movable contact from opento closed position, means for locking the contacts closed, spring meansat all times biasing the contacts toward open position, and a lostmotion connection between said handle and said movable contact carrierand including means to release the locking means, said lost motionconnection providing for limited idle operation of said handle inrelation to the locking means followed by release of the locking meansby the handle upon further operation thereof in the releasing direction,and said spring being effective thereafter to snap-open the contactsfree of inhibited action of said handle.

19. A circuit breaker including an insulating housing having an aperturetherein and containing the operative mechanism thereof, said mechanismincluding a fixed contact, a movable contact carrier bearing a movablecontact, an actuator and overload release means cooperable with eachother and carried by said movable contact carrier, a handle projectingfrom said aperture and operatively connected to said movable contactcarrier via said actuator to drive the movable contact from open toclosed position, said mechanism including yielding spring means and adetent arresting the closing motion of the movable contact member duringclosing operation of the handle, said yielding spring means producingsnap closing of the contacts after release of the detent, means lockingthe contacts closed, spring means at all times biasing the contactstoward open position, and a lost motion connection between said handleand said contact carrier effective to release the locking means andthereby enable said biasing spring to open the contacts despite possiblearresting of the handle part way toward open position after release ofsaid locking means.

References Cited in the file of this patent UNITED STATES PATENTS

